We used Elavil(the trade name)when our Nicholas(RIP)was spraying. He had some GI troubles, so we then switched to the transdermal version of the med. He did need his dose to be increased. Then did very nicely. Also, our vet suggested Feliway. After looking at Suzie, I can see that she is ONE very unhappy girl!!! Poor sweetheart!! There are some cats that just want to be the ONLY cat, and perhaps, she is one of them!! Have you considered an animal communicator? Also, have you looked into Bach Flower Remedies?? I hope that things work out for Suzie....good luck...Sandra